This is a study of blood fats being conducted in approximately 6 clinics across the United States involving a total of about 80 men and women, approximately 12 of whom will be enrolled at this site. Little is known about how the body uses fats that we eat during the day, although fats in the blood are believed to be linked to heart disease. Nor de we know how Zocor, (also called simvastatin) might reduce fats in the blood. Little is known as well about two enzymes, known as lipoprotein lipase and hepatic lipase, that are responsible for the removal of the particles in the blood stream that contain cholesterol and other fats including new fat that enters the body after people have eaten a meal. In this study we are trying to find out if we can use Zocor to reduce fats in the blood after a fatty meal, thus reducing the risk of developing atherosclerosis, the most common form of heart disease, and whether Zocor treatment favorably affects lipoprotein lipase and hepatic lipase.